CORE NETWORK NODE AND METHOD--TIME COORDINATED CELLS FOR EXTENDED DISCONTINUOUS RECEIVE (eDRX)

ABSTRACT

A core network node (e.g., Serving GPRS Support Node (SGSN)), a radio access network node (e.g., Base Station Subsystem), and various methods are described herein for realizing time coordinated cells and maintaining a reliability of paging a wireless device (e.g., Machine Type Communications (MTC) device, mobile station).

CLAIM OF PRIORITY

This application is a continuation application of U.S. patentapplication Ser. No. 15/154,708, filed on May 13, 2016, which claims thebenefit of priority to U.S. Provisional Application Ser. No. 62/163,794,filed on May 19, 2015, the entire contents of each of which are herebyincorporated herein by reference for all purposes.

RELATED PATENT APPLICATION

This application is related to the following co-filed application: U.S.application Ser. No. 15/154,724 entitled “Radio Access Network Node andMethod—Time Coordinated Cells for Extended Discontinuous Receive(eDRX)”. The entire contents of this document are hereby incorporatedherein by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to the wireless communicationsfield and, more particularly, to a core network node (e.g., Serving GPRSSupport Node (SGSN)), a radio access network node (e.g., Base StationSubsystem), and various methods for realizing time coordinated cells andmaintaining a reliability of paging a wireless device (e.g., MachineType Communications (MTC) device, mobile station).

BACKGROUND

The following abbreviations and terms are herewith defined, at leastsome of which are referred to within the following description of thepresent disclosure.

3GPP 3rd-Generation Partnership Project

AGCH Access Grant Channel ASIC Application Specific Integrated CircuitBLER Block Error Rate BLKS Blocks BSS Base Station Subsystem BSSGP BaseStation Subsystem General Packet Radio Service Protocol CC CoverageClass CN Core Network DRX Discontinuous Receive Cycle EC-GSM ExtendedCoverage Global System for Mobile Communications EC-PCH ExtendedCoverage Paging Channel

eDRX Extended Discontinuous Receive

eNB Evolved Node B DL Downlink DSP Digital Signal Processor

EDGE Enhanced Data rates for GSM Evolution

EGPRS Enhanced General Packet Radio Service FN Frame Number GSM GlobalSystem for Mobile Communications GERAN GSM/EDGE Radio Access NetworkGPRS General Packet Radio Service GPS Global Positioning System HARQHybrid Automatic Repeat Request IMSI International Mobile SubscriberIdentity IoT Internet of Things LLC Link Layer Control LTE Long-TermEvolution MCS Modulation and Coding Scheme MF Multiframe MFRM MultiframeMFRMS Multiframes MME Mobility Management Entity MS Mobile Station MTCMachine Type Communications NB Node B N-PDU Network Protocol Data UnitPCH Paging Channel PDN Packet Data Network PDTCH Packet Data TrafficChannel PDU Protocol Data Unit P-TMSI Packet Temporary Mobile SubscriberIdentity RACH Random Access Channel RAN Radio Access Network RAT RadioAccess Technology RAU Routing Area Update SGSN Serving GPRS Support NodeTDMA Time Division Multiple Access TLLI Temporary Logic Link IdentifierTS Technical Specifications UE User Equipment

uPoD device Study of Power saving for MTC Devices

WCDMA Wideband Code Division Multiple Access WiMAX WorldwideInteroperability for Microwave Access

Coverage Class (CC): At any point in time a wireless device belongs to aspecific uplink/downlink coverage class that corresponds to either thelegacy radio interface performance attributes that serve as thereference coverage for legacy cell planning (e.g., a Block Error Rate of10% after a single radio block transmission on the PDTCH) or a range ofradio interface performance attributes degraded compared to thereference coverage (e.g., up to 20 dB lower performance than that of thereference coverage). Coverage class determines the total number of blindtransmissions to be used when transmitting/receiving radio blocks. Anuplink/downlink coverage class applicable at any point in time candiffer between different logical channels. Upon initiating a systemaccess a wireless device determines the uplink/downlink coverage classapplicable to the RACH/AGCH based on estimating the number of blindtransmissions of a radio block needed by the BSS (radio access networknode) receiver/wireless device receiver to experience a BLER (blockerror rate) of approximately 10%. The BSS determines the uplink/downlinkcoverage class to be used by a wireless device on the assigned packetchannel resources based on estimating the number of blind transmissionsof a radio block needed to satisfy a target BLER and considering thenumber of HARQ retransmissions (of a radio block) that will, on average,be needed for successful reception of a radio block using that targetBLER. Note: a wireless device operating with radio interface performanceattributes corresponding to the reference coverage (normal coverage) isconsidered to be in the best coverage class (i.e., coverage class 1) andtherefore does not make any additional blind transmissions subsequent toan initial blind transmission. In this case, the wireless device may bereferred to as a normal coverage wireless device. In contrast, awireless device operating with radio interface performance attributescorresponding to an extended coverage (i.e., coverage class greaterthan 1) makes multiple blind transmissions. In this case, the wirelessdevice may be referred to as an extended coverage wireless device.Multiple blind transmissions corresponds to the case where N instancesof a radio block are transmitted consecutively using the applicableradio resources (e.g., the paging channel) without any attempt by thetransmitting end to determine if the receiving end is able tosuccessfully recover the radio block prior to all N transmissions. Thetransmitting end does this in attempt to help the receiving end realizea target BLER performance (e.g., target BLER≤10% for the pagingchannel).eDRX cycle: eDiscontinuous reception (eDRX) is a process of a wirelessdevice disabling its ability to receive when it does not expect toreceive incoming messages and enabling its ability to receive during aperiod of reachability when it anticipates the possibility of messagereception. For eDRX to operate, the network coordinates with thewireless device regarding when instances of reachability are to occur.The wireless device will therefore wake up and enable message receptiononly during pre-scheduled periods of reachability. This process reducesthe power consumption which extends the battery life of the wirelessdevice and is sometimes called (deep) sleep mode.Extended Coverage: The general principle of extended coverage is that ofusing blind transmissions for the control channels and for the datachannels to realize a target block error rate performance (BLER) for thechannel of interest. In addition, for the data channels the use of blindtransmissions assuming MCS-1 (i.e., the lowest modulation and codingscheme (MCS) supported in EGPRS today) is combined with HARQretransmissions to realize the needed level of data transmissionperformance. Support for extended coverage is realized by definingdifferent coverage classes. A different number of blind transmissionsare associated with each of the coverage classes wherein extendedcoverage is associated with coverage classes for which multiple blindtransmissions are needed (i.e., a single blind transmission isconsidered as the reference coverage). The number of total blindtransmissions for a given coverage class can differ between differentlogical channels.MTC device: A MTC device is a type of device where support for humaninteraction with the device is typically not required and datatransmissions from or to the device are expected to be rather short(e.g., a maximum of a few hundred octets). MTC devices supporting aminimum functionality can be expected to only operate using normal cellcontours and as such do not support the concept of extended coveragewhereas MTC devices with enhanced capabilities may support extendedcoverage.uPoD device: A uPoD device is similar to a MTC device except it alsosupports the mandatory use of a power saving state known as eDRX orPower Saving Mode (PSM) which allows for substantial battery savings tobe realized in packet idle mode.Nominal Paging Group: The specific set of EC-PCH blocks a devicemonitors once per eDRX cycle. The device determines this specific set ofEC-PCH blocks using an algorithm that takes into account its IMSI, itseDRX cycle length and its downlink coverage class.

The need to support MTC devices using cellular technologies isincreasing because the cellular technologies represent existing (andtherefore convenient) deployments of service areas in which MTC devicescan operate. As a result, more and more MTC devices are being deployedin wireless communication networks. One challenge facing the deploymentof MTC devices in wireless communication networks is that the MTCdevices will typically not have access to external power and, as such,will need to make use of batteries with target lifetimes in the area ofyears. To help realize such battery lifetimes, the use of extendeddiscontinuous receive (eDRX) functionality may be seen as necessary,where eDRX cycle lengths will be in the area of minutes to hours (i.e.,a MTC device will support one paging occasion per eDRX cycle), comparedto legacy operation, where discontinuous receive (DRX) cycle lengths arein the area of a few seconds. The possibility of MTC device mobilityalso needs to be taken into account including the issue of how thereachability of a MTC device (e.g., using the MTC device's pagingoccasion) will be impacted as a result of the possible mobility of theMTC device.

The paging occasion (nominal paging group) used by a wireless device(e.g., MS, MTC device) on the radio interface is currently determined,at least in part, by the radio frame number. This is described inmultiple 3GPP TSs such as, for example, 3GPP TS 36.331 V.12.5.0 (dated2015 Mar. 27), 3GPP TS 45.002 V.12.4.0 (dated 2015 Mar. 21), and 3GPP TS25.304 V.12.5.0 (dated 2015 Mar. 23) (the contents of these documentsare incorporated herein by reference for all purposes). A problem withthis technique is that the cycle of radio frame numbers in differentcells will appear on the radio interface in an uncoordinated manner inthe time domain (i.e., when paging a wireless device in a given pagingarea comprising multiple cells, the corresponding paging message will besent on the radio interface to different cells at different points intime).

With this lack of time coordination, the spread between paging occasionsfor the same wireless device in different cells can be up to the maximumextended DRX cycle length, since the same radio frame number associatedwith the start of a nominal paging group can occur at different times indifferent cells. Therefore, the lack of time coordinated cells has somedrawbacks when considered within the context of eDRX. Some of thesedrawbacks are as follows:

-   -   Drawback 1: A wireless device might be unreachable for paging,        as the wireless device might miss its paging opportunities (in        different cells) as a result of the wireless device moving        between cells.    -   Drawback 2: A wireless device might receive and respond to the        same paging message multiple times (in different cells) as a        result of the wireless device moving between cells.    -   Drawback 3: Temporary identifiers (e.g., Packet Temporary Mobile        Subscriber Identity (P-TMSI)) included in the paging message        might become invalid if the paging messages are buffered in the        radio access network (RAN) node for extended time periods (e.g.,        P-TMSI re-allocation could occur while a page with that P-TMSI        is buffered). If this happens, then if the buffered page is        eventually sent, this could then lead to either a paging failure        (e.g., the intended wireless device is not paged) or, at least,        a waste of paging bandwidth. To mitigate these problems,        additional signaling and complexity would need to be introduced.

This lack of time coordinated cells and the resulting paging problem isaddressed by the present disclosure.

SUMMARY

A CN node (e.g., SGSN), a RAN node (e.g., BSS), and various methods foraddressing the aforementioned drawbacks are described in the independentclaims. Advantageous embodiments of the CN node (e.g., SGSN), the RANnode (e.g., BSS), and various methods are further described in thedependent claims.

In one aspect, the present disclosure provides a CN node configured tointeract with a plurality of RAN nodes to time coordinate a plurality ofcells and maintain a reliability of paging a wireless device. The CNnode comprises a processor and a memory that stores processor-executableinstructions, wherein the processor interfaces with the memory toexecute the processor-executable instructions, whereby the CN node isoperable to obtain, from one of the RAN nodes, information indicating atime remaining until a next paging opportunity for the wireless devicewithin the cells comprising a paging area of the wireless device. The CNnode can obtain the time remaining until a next paging opportunity forthe wireless device utilizing, for example, a modified Routing AreaUpdate (RAU) procedure, a modified paging procedure, or a new dummypaging procedure. An advantage of the CN node implementing the obtainoperation is that helps to address the lack of time coordinated cellsand the resulting paging problem that adversely affects the legacywireless communication system.

In another aspect, the present disclosure provides a method in a CN nodefor interacting with a plurality of RAN nodes to time coordinate aplurality of cells and maintain a reliability of paging a wirelessdevice. The method comprises an obtaining step. In the obtaining step,the CN node obtains, from one of the RAN nodes, information indicating atime remaining until a next paging opportunity for the wireless devicewithin the cells comprising a paging area of the wireless device. The CNnode can obtain the time remaining until a next paging opportunity forthe wireless device utilizing, for example, a modified Routing AreaUpdate (RAU) procedure, a modified paging procedure, or a new dummypaging procedure. An advantage of the CN node implementing the obtainingstep is that this helps to address the lack of time coordinated cellsand the resulting paging problem that adversely affects the legacywireless communication system.

In another aspect, the present disclosure provides a CN node comprisinga processor and a memory that stores processor-executable instructions,wherein the processor interfaces with the memory to execute theprocessor-executable instructions, whereby the CN node is operable toperform a send operation and a receive operation. In the send operation,the CN node sends, to a RAN node, a dummy paging request associated witha wireless device. In the receive operation, the CN node receives, fromthe RAN node, a dummy paging response which includes a time remaininguntil a next paging opportunity for the wireless device. The CN node cansend the dummy paging request as frequently or infrequently as desiredto determine the time remaining until the next paging opportunity forthe wireless device. Further, the dummy paging request is defined suchthat the RAN node is not required to send a paging message on the radiointerface to the wireless device but instead calculates the timeremaining until a next paging opportunity for the wireless device andsends the time remaining until a next paging opportunity for thewireless device to the CN node. An advantage of the CN node implementingthe obtaining step is that this helps to address the lack of timecoordinated cells and the resulting paging problem that adverselyaffects the legacy wireless communication system.

In yet another aspect, the present disclosure provides a method in a CNnode for time coordinating a plurality of cells and maintaining areliability of paging a wireless device. The method comprises a sendingstep and a receiving step. In the sending step, the CN node sends, to aRAN node, a dummy paging request associated with a wireless device. Inthe receive operation, the CN node receives, from the RAN node, a dummypaging response which includes a time remaining until a next pagingopportunity for the wireless device. The CN node can send the dummypaging request as frequently or infrequently as desired to determine thetime remaining until the next paging opportunity for the wirelessdevice. Further, the dummy paging request is defined such that the RANnode is not required to send a paging message on the radio interface tothe wireless device but instead calculates the time remaining until anext paging opportunity for the wireless device and sends the timeremaining until a next paging opportunity for the wireless device to theCN node. An advantage of the CN node implementing the sending andreceiving steps is that this helps to address the lack of timecoordinated cells and the resulting paging problem that adverselyaffects the legacy wireless communication system.

Additional aspects of the present disclosure will be set forth, in part,in the detailed description, figures and any claims which follow, and inpart will be derived from the detailed description, or can be learned bypractice of the invention. It is to be understood that both theforegoing general description and the following detailed description areexemplary and explanatory only and are not restrictive of the presentdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present disclosure may be obtainedby reference to the following detailed description when taken inconjunction with the accompanying drawings:

FIG. 1 is a diagram of an exemplary wireless communication network whichincludes a CN node, multiple RAN nodes, and multiple wireless deviceswhich are all configured in accordance with an embodiment of the presentdisclosure;

FIG. 2 is a signal diagram illustrating a modified RAU procedure thatsupports time coordinated cells in accordance with an embodiment of thepresent disclosure;

FIG. 3 is a signal diagram illustrating a modified paging procedure thatsupports time coordinated cells in accordance with an embodiment of thepresent disclosure;

FIG. 4 is a signal diagram illustrating a dummy paging procedure thatsupports time coordinated cells in accordance with an embodiment of thepresent disclosure;

FIG. 5 is a diagram used to explain an exemplary way that a RAN node cancalculate a time remaining until a next paging opportunity for awireless device;

FIG. 6 is a flowchart of a method implemented in the CN node inaccordance with an embodiment of the present disclosure;

FIG. 7 is a block diagram illustrating a structure of the CN nodeconfigured in accordance with an embodiment of the present disclosure;

FIG. 8 is a flowchart of another method implemented in the CN node inaccordance with an embodiment of the present disclosure;

FIG. 9 is a block diagram illustrating another structure of the CN nodeconfigured in accordance with an embodiment of the present disclosure;

FIG. 10 is a flowchart of a method implemented in the RAN node inaccordance with an embodiment of the present disclosure;

FIG. 11 is a block diagram illustrating a structure of the RAN nodeconfigured in accordance with an embodiment of the present disclosure;

FIG. 12 is a flowchart of another method implemented in the RAN node inaccordance with an embodiment of the present disclosure; and

FIG. 13 is a block diagram illustrating another structure of the RANnode configured in accordance with an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

A discussion is provided first herein to describe an exemplary wirelesscommunication network that includes a CN node (e.g., SGSN, MME),multiple RAN nodes (e.g., BSSs, NodeBs, eNodeBs), and multiple wirelessdevices (e.g., MSs, MTC devices) in accordance with an embodiment of thepresent disclosure (see FIG. 1). Then, a discussion is provided todisclose different techniques that the CN node (e.g., SGSN, MME) and theRAN nodes (e.g., BSSs, NodeBs, eNodeBs) can use to realize timecoordinated cells and maintain a reliability of paging a wireless devicein accordance with various embodiments of the present disclosure (seeFIGS. 2-5). Thereafter, a discussion is provided to explain the basicfunctionalities-configurations of the CN node (e.g., SGSN, MME) and theRAN node (e.g., BSS, NodeB, eNodeB) in accordance with differentembodiments of the present disclosure (see FIGS. 6-13).

Exemplary Wireless Communication Network 100

Referring to FIG. 1, there is illustrated an exemplary wirelesscommunication network 100 in accordance with the present disclosure. Thewireless communication network 100 includes a core network 106 (whichcomprises at least one CN node 107) and multiple RAN nodes 102 ₁ and 102₂ (only two shown) which interface with multiple wireless devices 104 ₁,104 ₂, 104 ₃ . . . 104 _(n). The wireless communication network 100 alsoincludes many well-known components, but for clarity, only thecomponents needed to describe the features of the present disclosure aredescribed herein. Further, the wireless communication network 100 isdescribed herein as being a GSM/EGPRS wireless communication network 100which is also known as an

EDGE wireless communication network 100. However, those skilled in theart will readily appreciate that the techniques of the presentdisclosure which are applied to the GSM/EGPRS wireless communicationnetwork 100 are generally applicable to other types of wirelesscommunication systems, including, for example, WCDMA, LTE, and WiMAXsystems.

The wireless communication network 100 includes the RAN nodes 102 ₁ and102 ₂ (wireless access nodes—only two shown) which provide networkaccess to the wireless devices 104 ₁, 104 ₂, 104 ₃ . . . 104 _(n). Inthis example, the RAN node 102 ₁ is providing network access to wirelessdevice 104 ₁ while the RAN node 102 ₂ is providing network access towireless devices 104 ₂, 104 ₃ . . . 104 _(n). The RAN nodes 102 ₁ and102 ₂ are connected to the core network 106 (e.g., SGSN core network106) and, in particular, to the CN node 107 (e.g., SGSN 107). The corenetwork 106 is connected to an external packet data network (PDN) 108,such as the Internet, and a server 110 (only one shown). The wirelessdevices 104 ₁, 104 ₂, 104 ₃ . . . 104 _(n) may communicate with one ormore servers 110 (only one shown) connected to the core network 106and/or the PDN 108.

The wireless devices 104 ₁, 104 ₂, 104 ₃ . . . 104 _(n) may refergenerally to an end terminal (user) that attaches to the wirelesscommunication network 100, and may refer to either a MTC device (e.g., asmart meter) or a non-MTC device. Further, the term “wireless device” isgenerally intended to be synonymous with the term mobile device, mobilestation (MS). “User Equipment,” or UE, as that term is used by 3GPP, andincludes standalone wireless devices, such as terminals, cell phones,smart phones, tablets, cellular IoT devices, IoT devices, andwireless-equipped personal digital assistants, as well as wireless cardsor modules that are designed for attachment to or insertion into anotherelectronic device, such as a personal computer, electrical meter, etc.

Likewise, unless the context clearly indicates otherwise, the term RANnode 102 ₁ and 102 ₂ (wireless access node 102 ₁ and 102 ₂) is usedherein in the most general sense to refer to a base station, a wirelessaccess node, or a wireless access point in a wireless communicationnetwork 100, and may refer to RAN nodes 102 ₁ and 102 ₂ that arecontrolled by a physically distinct radio network controller as well asto more autonomous access points, such as the so-called evolved Node Bs(eNodeBs) in Long-Term Evolution (LTE) networks.

Each wireless device 104 ₁, 104 ₂, 104 ₃ . . . 104 _(n) may include atransceiver circuit 110 ₁, 110 ₂, 110 ₃ . . . 110 _(n) for communicatingwith the RAN nodes 102 ₁ and 102 ₂, and a processing circuit 112 ₁, 112₂, 112 ₃ . . . 112 _(n) for processing signals transmitted from andreceived by the transceiver circuit 110 ₁, 110 ₂, 110 ₃ . . . 110 _(n)and for controlling the operation of the corresponding wireless device104 ₁, 104 ₂, 104 ₃ . . . 104 _(n). The transceiver circuit 110 ₁, 110₂, 110 ₃ . . . 110 _(n) may include a transmitter 114 ₁, 114 ₂, 114 ₃ .. . 114 _(n) and a receiver 116 ₁, 116 ₂, 116 ₃ . . . 116 _(n), whichmay operate according to any standard, e.g., the GSM/EDGE standard. Theprocessing circuit 112 ₁, 112 ₂, 112 ₃ . . . 112 _(n) may include aprocessor 118 ₁, 118 ₂, 118 ₃ . . . 118 _(n) and a memory 120 ₁, 120 ₂,120 ₃ . . . 120 _(n) for storing program code for controlling theoperation of the corresponding wireless device 104 ₁, 104 ₂, 104 ₃ . . .104 _(n). The program code may include code for performing theprocedures (e.g., transmitting an LLC PDU comprising a RAU Requestmessage, receiving an LLC PDU comprising a RAU Accept message, andtransmitting an LLC PDU comprising a RAU Complete message) as describedhereinafter.

Each RAN node 102 ₁ and 102 ₂ (wireless access node 102 ₁ and 102 ₂) mayinclude a transceiver circuit 122 ₁ and 122 ₂ for communicating withwireless devices 104 ₁, 104 ₂, 104 ₃ . . . 104 _(n), a processingcircuit 124 ₁ and 124 ₂ for processing signals transmitted from andreceived by the transceiver circuit 122 ₁ and 122 ₂ and for controllingthe operation of the corresponding RAN node 102 ₁ and 102 ₂, and anetwork interface 126 ₁ and 126 ₂ for communicating with the corenetwork 106. The transceiver circuit 122 ₁ and 122 ₂ may include atransmitter 128 ₁ and 128 ₂ and a receiver 130 ₁ and 130 ₂, which mayoperate according to any standard, e.g., the GSM/EDGE standard. Theprocessing circuit 124 ₁ and 124 ₂ may include a processor 132 ₁ and 132₂, and a memory 134 ₁ and 134 ₂ for storing program code for controllingthe operation of the corresponding RAN node 102 ₁ and 102 ₂. The programcode may include code for performing the procedures (e.g., receiving anLLC PDU comprising a RAU Request message, transmitting/receiving a BSSGPPDU comprising the RAU Request message, receiving/transmitting a BSSGPPDU comprising a RAU Accept message, IMSI, eDRX cycle length, andcoverage class (not applicable for Study of Power Saving for MTC Devices(uPoD devices)), transmitting an LLC PDU comprising the RAU Acceptmessage, receiving an LLC PDU comprising a RAU Complete message,calculating a time remaining until the next paging opportunity,transmitting/receiving a BSSGP PDU comprising the RAU Complete messageand the time remaining until the next paging opportunity) as describedhereinafter with respect to FIGS. 10 and 12.

The CN node 107 (e.g., SGSN 107, MME 107) may include a transceivercircuit 136 for communicating with the RAN nodes 102 ₁ and 102 ₂, aprocessing circuit 138 for processing signals transmitted from andreceived by the transceiver circuit 136 and for controlling theoperation of the CN node 107, a network interface 140 for communicatingwith the RAN nodes 102 ₁ and 102 ₂, and an eDRX cycle timer 158 fordetermining the periodicity of paging opportunities for wireless devices104 ₁, 104 ₂, 104 ₃ . . . 104 g. The transceiver circuit 136 may includea transmitter 142 and a receiver 144, which may operate according to anystandard, e.g., the GSM/EDGE standard. The processing circuit 138 mayinclude a processor 146 and a memory 148 for storing program code forcontrolling the operation of the CN node 107. The program code mayinclude code for performing the procedures as described hereinafter withrespect to FIGS. 6 and 8.

Time Coordinated Cells and Reliability of Paging a Wireless Device

Realizing Time Coordinated Cells-Radio Interface

One aspect of the present disclosure involves the coordination of pagingoccasions across the radio interface of multiple cells 152 ₁ and 152 ₂(for example), thus mitigating the drawbacks resulting from using eDRXas described above in the Background Section. This means that eachpaging occasion of a wireless device 104 ₂ (for example) needs to occurat approximately the same time (e.g., within a certain timing accuracy)over the radio interface for each cell 152 ₁ and 152 ₂ in the set ofcells 152 ₁ and 152 ₂ used for paging that wireless device 104 ₂ (seeFIG. 1). In the illustrated example associated with FIG. 1, the wirelessdevice 104 ₂ is currently located in cell 152 ₁ but it has a paging area154 that includes cells 152 ₁ and 152 ₂ where the RAN node 102 ₁ managescell 152 ₁ and the RAN node 102 ₂ manages cell 152 ₂.

In general it should be appreciated that per the present disclosure thegreater the number of cells within each set of time coordinated cells,the greater the mitigation of the drawbacks described above in theBackground Section. Further, the greatest mitigation of these drawbackswill be realized if the paging area consists of a set of timecoordinated cells, wherein the paging occasion for any wireless devicein that paging area occurs at approximately the same time (e.g., withina predetermined time period) on the respective radio interfaces of thesecells.

Realizing Time Coordinated Cells—CN Node 107 (e.g., SGSN 107)

One aspect of the present disclosure involves the CN node 107 (e.g.,SGSN 107) having knowledge of when the paging occasion of a wirelessdevice 104 ₂ (for example) is approaching within the set of cells 152 ₁and 152 ₂ comprising the paging area 154 of that wireless device 104 ₂.This can be realized as follows: upon receiving a LLC PDU (containing aRAU Complete message) from a wireless device 104 ₂ (for example), a RANnode 102 ₂ (e.g., BSS 102 ₂) that has knowledge of the InternationalMobile Subscriber Identity (IMSI), eDRX cycle length, and coverage class(not applicable for Study of Power Saving for MTC Devices (uPoDdevices)) of the corresponding wireless device 104 ₂ (for example) shallcalculate the time remaining until the next paging opportunity 156(i.e., in minutes and seconds) for that wireless device 104 ₂.Thereafter, the RAN node 102 ₂ (e.g., BSS 102 ₂) will forward thereceived LLC PDU and the corresponding time remaining until the nextpaging opportunity 156 information to the CN node 107 (e.g., SGSN 107).An example, of the reception of a LLC PDU from a wireless device 104 ₂(for example) wherein the RAN node 102 ₂ already has the information itneeds to calculate the time remaining until the next paging opportunity156 for that wireless device 104 ₂ can occur within the context of amodified RAU procedure as shown in FIG. 2. Several exemplary ways thatthe CN node 107 (e.g., SGSN 107) can obtain the time remaining until thenext paging opportunity 156 for any one of the wireless devices 104 ₁,104 ₂, 104 ₃ . . . 104 _(n) are discussed below with respect to FIGS.2-4.

Referring to FIG. 2, there is a signal diagram illustrating a modifiedRAU procedure that supports time coordinated cells in accordance with anembodiment of the present disclosure. Basically, the legacy Routing AreaUpdate (RAU) procedure can be modified so that the RAU procedure can beused in accordance with an embodiment of the present disclosure as anopportunity for the CN node 107 (e.g., SGSN 107) to provide the RAN node102 ₂ (e.g., BSS 102 ₂) with the information (e.g., TLLI-specificparameters) that the RAN node 102 ₂ (e.g., BSS 102 ₂) uses to calculatethe time remaining until the next paging opportunity 156 and provide thecalculated time remaining until the next paging opportunity 156 to theCN node 107. An exemplary modified RAU procedure in accordance with anembodiment of the present disclosure can have the following steps:

1. The wireless device 104 ₂ (for example) transmits a LLC PDU 202 whichcontains a RAU Request to the RAN node 102 ₂ (e.g., BSS 102 ₂).

2. The RAN node 102 ₂ (e.g., BSS 102 ₂) transmits a BSSGP PDU 204 whichcontains the RAU Request to the CN node 107 (e.g., SGSN 107).

3. The CN node 107 (e.g., SGSN 107) transmits a BSSGP PDU 206 whichcontains a RAU Accept and the wireless device 104 ₂'s IMSI, eDRX cycle,and coverage class (e.g., the wireless device 104 ₂'s TLLI specificparameters) to the RAN node 102 ₂ (e.g., BSS 102 ₂). It should be notedthat by including the wireless device 104 ₂'s IMSI, eDRX cycle length,and coverage class information within the BSSGP PDU 206 which is used tosend (step 3) the RAU Accept to the RAN node 102 ₂ (e.g., BSS 102 ₂),the RAN node 102 ₂ (e.g., BSS 102 ₂) can now calculate (step 6) the nextpaging occasion and in particular the time remaining until the nextpaging opportunity 156 for the wireless device 104 ₂ to which the RAUAccept is being sent. Further, the RAN node 102 ₂ (e.g., BSS 102 ₂) canretain these TLLI specific parameters (e.g., IMSI, eDRX cycle length,and coverage class) for a certain minimum amount of time (e.g., 10seconds).

4. The RAN node 102 ₂ (e.g., BSS 102 ₂) transmits a LLC PDU 208 whichcontains the RAU Accept to the wireless device 104 ₂.

5. The wireless device 104 ₂ transmits a LLC PDU 210 which contains aRAU Complete to the RAN node 102 ₂ (e.g., BSS 102 ₂).

6. The RAN node 102 ₂ (e.g., BSS 102 ₂) calculates the time remaininguntil the next paging opportunity 156 for the wireless device 104 ₂.Basically, if the RAN node 102 ₂ (e.g., BSS 102 ₂) receives (step 5) anuplink LLC PDU from the wireless device 104 ₂ having a TLLI for whichthe RAN node 102 ₂ (e.g., BSS 102 ₂) still has these TLLI specificparameters, then the RAN node 102 ₂ (e.g., BSS 102 ₂) will calculate(step 6) the time remaining until the next paging opportunity 156 andinclude this time remaining until the next paging opportunity 156information along with the received uplink LLC PDU within the BSSGP PDU212 that the RAN node 102 ₂ (e.g., BSS 102 ₂) sends (step 7) to the CNnode 107 (e.g., SGSN 107). An example of how the RAN node 102 ₂ (e.g.,BSS 102 ₂) can calculate the time remaining until the next pagingopportunity 156 is provided below with respect to TABLE 1 and FIG. 5.

7. The RAN node 102 ₂ (e.g., BSS 102 ₂) transmits a BSSGP PDU 212 whichcontains the RAU Complete and the time remaining until the next pagingopportunity 156 for the wireless device 104 ₂ to the CN node 107 (e.g.,SGSN 107).

Note: Steps 3, 6 and 7 involve new functionality when comparing thelegacy RAU procedure and the modified RAU procedure in accordance withthe present disclosure. A discussion is provided below which describessome exemplary ways that the CN node 107 (e.g., SGSN 107) can utilizethe time remaining until the next paging opportunity 156 to realize timecoordinated cells 152 ₁ and 152 ₂ and maintain a reliability of pagingthe wireless device 104 ₂ in accordance with the present disclosure.

Referring to FIG. 3, there is a signal diagram illustrating a modifiedpaging procedure that supports time coordinated cells in accordance withan embodiment of the present disclosure. Basically, the legacy pagingprocedure can be modified so that the paging procedure can be used inaccordance with an embodiment of the present disclosure as anopportunity for the CN node 107 (e.g., SGSN 107) to provide the RAN node102 ₂ (e.g., BSS 102 ₂) with the information (e.g., TLLI specificparameters) that the RAN node 102 ₂ (e.g., BSS 102 ₂) uses to calculatethe time remaining until the next paging opportunity 156 and provide thecalculated time remaining until the next paging opportunity 156 to theCN node 107. An exemplary modified paging procedure in accordance withan embodiment of the present disclosure can have the following steps:

1. The CN node 107 (e.g., SGSN 107) transmits a paging request 302 tothe RAN node 102 ₂ (e.g., BSS 102 ₂). The paging request 302 includesthe wireless device 104 ₂'s IMSI, eDRX cycle, and coverage class (e.g.,the wireless device 104 ₂'s TLLI specific parameters). The RAN node 102₂ stores the TLLI specific parameters needed to calculate the nextpaging opportunity 156 for the indicated wireless device 104 ₂ for acertain minimum amount of time (e.g., 10 seconds).

2. The RAN node 102 ₂ (e.g., BSS 102 ₂) transmits a paging request 304to the wireless device 104 ₂.

3. The wireless device 104 ₂ transmits a paging response 306 to the RANnode 102 ₂ (e.g., BSS 102 ₂).

4. The RAN node 102 ₂ (e.g., BSS 102 ₂) calculates the time remaininguntil the next paging opportunity 156 for the wireless device 104 ₂. Anexample of how the RAN node 102 ₂ (e.g., BSS 102 ₂) can calculate thetime remaining until the next paging opportunity 156 is provided belowwith respect to TABLE 1 and FIG. 5.

5. The RAN node 102 ₂ (e.g., BSS 102 ₂) transmits a page response 308which contains the time remaining until the next paging opportunity 156for the wireless device 104 ₂ to the CN node 107 (e.g., SGSN 107).

Note: Steps 1, 4 and 5 involve new functionality when comparing thelegacy paging procedure to the modified paging procedure in accordancewith the present disclosure. A discussion is provided below whichdescribes some exemplary ways that the CN node 107 (e.g., SGSN 107) canutilize the time remaining until the next paging opportunity 156 torealize time coordinated cells 152 ₁ and 152 ₂ and maintain areliability of paging the wireless device 104 ₂ in accordance with thepresent disclosure.

Referring to FIG. 4, there is a signal diagram illustrating how to use adummy paging procedure to support time coordinated cells in accordancewith an embodiment of the present disclosure. An exemplary dummy pagingprocedure in accordance with another embodiment of the presentdisclosure can have the following steps:

1. The CN node 107 (e.g., SGSN 107) transmits a dummy paging request 402to the RAN node 102 ₂ (e.g., BSS 102 ₂). The dummy paging request 402includes the wireless device 104 ₂'s IMSI, eDRX cycle, and coverageclass (e.g., the wireless device 104 ₂'s TLLI specific parameters).Further, the dummy paging request 402 is defined to trigger the RAN node102 ₂ (e.g., BSS 102 ₂) to calculate (step 2) the time remaining untilthe next paging opportunity 156 for the wireless device 104 ₂ and thentransmit (step 3) a corresponding dummy paging response 404 whichincludes the time remaining until the next paging opportunity 156 forthe wireless device 104 ₂ to the CN node 107 (e.g., SGSN 107). In thisexample, the RAN node 102 ₂ (e.g., BSS 102 ₂) upon receiving thespecially defined dummy paging request 402 does not transmit a pagingmessage over a radio interface to the wireless device 104 ₂.

2. The RAN node 102 ₂ (e.g., BSS 102 ₂) calculates the time remaininguntil the next paging opportunity 156 for the wireless device 104 ₂. Anexample of how the RAN node 102 ₂ (e.g., BSS 102 ₂) can calculate thetime remaining until the next paging opportunity 156 is provided belowwith respect to TABLE 1 and FIG. 5.

3. The RAN node 102 ₂ (e.g., BSS 102 ₂) transmits a dummy page response404 which contains the time remaining until the next paging opportunity156 for the wireless device 104 ₂ to the CN node 107 (e.g., SGSN 107).The dummy paging mechanism associated with steps 1 and 3, allows the CNnode 107 (e.g., SGSN 107) to verify its understanding of when the nextpaging opportunity will occur for a given wireless device 104 ₂ (forexample), and therefore, may be used as frequently or infrequently asdesired by the CN node 107 (e.g., SGSN 107).

Note: Steps 1, 2 and 3 are associated with a new dummy paging procedurein accordance with the present disclosure. A discussion is providedbelow which describes some exemplary ways that the CN node 107 (e.g.,SGSN 107) can utilize the time remaining until the next pagingopportunity 156 to realize time coordinated cells 152 ₁ and 152 ₂ andmaintain a reliability of paging the wireless device 104 ₂ in accordancewith the present disclosure.

In continuing the discussion associated with the various proceduresdiscussed above with respect to FIGS. 2-4, the CN node 107 (e.g., SGSN107) can use the received time remaining until the next pagingopportunity 156 along with its knowledge of the wireless device-specificeDRX cycle length (e.g., established during the legacy RAU procedure orthe modified RAU procedure of FIG. 2) to maintain a wirelessdevice-specific eDRX cycle timer 158 to determine the periodicity ofpaging opportunities for the wireless device 104 ₂ (for example). Thevalue of the eDRX cycle timer 158 remains valid for the wireless device104 ₂ (unless it is modified due to reception of new eDRX cycleinformation or a new value for time remaining until the next pagingopportunity 156) regardless of whether the CN node 107 (e.g., SGSN 107)actually triggers the transmission of a page to that wireless device 104₂ using any of the ongoing paging opportunities.

The CN node 107 (e.g., SGSN 107) uses the reception of an LLC PDU (e.g.,FIG. 2's BSSGP PDU 212, FIG. 3's paging response 308, FIG. 4's dummypaging response 404), including the time remaining until the next pagingopportunity 156 as an opportunity to verify its understanding of theperiodicity of paging opportunities for the associated wireless device104 ₂. If an LLC PDU (e.g., FIG. 2's BSSGP PDU 212, FIG. 3's pagingresponse 308, FIG. 4's dummy paging response 404) indicates a nextpaging opportunity that is different from when the CN node 107 (e.g.,SGSN 107) expected the next paging opportunity to occur, then the CNnode 107 (e.g., SGSN 107) will modify the eDRX cycle timer 158accordingly for the corresponding wireless device 104 ₂.

The CN node 107 (e.g., SGSN 107) can set the eDRX cycle timer 158 toexpire a predetermined time (e.g., few seconds) before the next pagingopportunity to ensure the paging requests (if any) for wireless device104 ₂ arrive at the set of RAN nodes 102 ₁ and 102 ₂ (BSS 102 ₁ and 102₂) associated with the paging area 154 of the wireless device 104 ₂before the paging opportunity for the wireless device 104 ₂ occurs onthe radio interfaces of the time coordinated cells 152 ₁ and 152 ₂. Inthis regard, the CN node 107 (e.g., SGSN 107) creates a paging requestupon the reception of a N-PDU for the wireless device 104 ₂, and thepaging request is buffered in the CN node 107 (e.g., SGSN 107) until theexpiration of the eDRX cycle timer 158 of the corresponding wirelessdevice 104 ₂. If there is a buffered paging request when the eDRX cycletimer 158 expires, then the CN node 107 (e.g., SGSN 107) transmitspaging requests to the appropriate set of RAN nodes 102 ₁ and 102 ₂(e.g., BSS 102 ₁ and 102 ₂) which are managing the cells 152 ₁ and 152 ₂of the applicable paging area 154 of the wireless device 104 ₂) andrestarts the eDRX cycle timer 158. Upon receiving the paging request,the RAN nodes 102 ₁ and 102 ₂ (e.g., BSS 102 ₁ and 102 ₂) each calculatethe precise and substantially same paging opportunity on the radiointerface of the cell 152 ₁ and 152 ₂ that it manages using the IMSI,the eDRX cycle length and the coverage class (absent for uPoD devices)information included within the paging request for the wireless device104 ₂. On the other hand, if there is no buffered paging request whenthe eDRX cycle timer 158 expires, then the CN node 107 (e.g., SGSN 107)restarts the eDRX cycle timer 158 based on its knowledge of the eDRXcycle length of the wireless device 104 ₂.

One exemplary way the RAN node 102 ₂ (for example) can calculate thetime remaining until the next paging opportunity 156 has been describedin GP-150133 entitled “EC-GSM-Paging Group Determination” and GP-150259entitled “Pseudo CR 45.820-EC-GSM, Paging Group Determination” bothsubmitted to GERAN #65, Mar. 9th-13th, 2015 (the contents of thesedocuments are incorporated herein by reference for all purposes). Inthis example, when sending a paging request to the RAN node 102 ₂ (e.g.,BSS 102 ₂), the CN node 107 (e.g., SGSN 107) includes an indication ofthe eDRX cycle, DL CC and IMSI associated with the target wirelessdevice 104 ₂ (for example) thereby allowing the RAN node 102 ₂ todetermine the next occurrence of the nominal paging group for thatwireless device 104 ₂ within its eDRX cycle as follows:

-   -   N is the number of paging groups corresponding to a given DL CC        within a given eDRX cycle and is determined based on        EXTENDED_DRX_MFRMS, EC_PCH_BLKS_MFRM, and CC_EC_PCH_BLKS where:        -   EXTENDED_DRX_MFRMS is the number of 51-multiframes per eDRX            cycle determined as per TABLE 1 (GP-150133's_Table 1) below.        -   EC_PCH_BLKS_MFRM indicates the number of EC-PCH blocks            (i.e., the number of 2 bursts blocks) per 51-multiframe. For            EC-GSM this can be fixed at 16 which is the equivalent of            the legacy PCH BLKS MFRM parameter indicating 8 PCH blocks            per 51-multiframe.        -   CC_EC_PCH_BLKS is the number of EC-PCH blocks required for a            given DL CC (where the number of blind transmission required            for any given DL CC is pre-defined by the specifications).    -   The set of eDRX cycle lengths identified by TABLE 1 (GP-150133's        Table 1) is selected such that each member of the set occurs an        integral number of times within the full TDMA FN space.    -   N=(EC_PCH_BLKS_MFRM×EXTENDED_DRX_MFRMS)/CC_EC_PCH_BLKS. The        EC-PCH CC1 block for a device using a given eDRX cycle is        determined based on where the nominal paging group occurs for DL        CC=1 (i.e., CC_EC_PCH_BLKS=1)    -   EC-PCH CC1 block=mod (IMSI, N) where        N=(16×EXTENDED_DRX_MFRMS)/1.

TABLE 1 Set of eDRX Cycles Supported eDRX Cycle Value Target eDRX Numberof 51-MF per eDRX Cycle eDRX Cycles per (EXTENDED_DRX) Cycle Length(EXTENDED_DRX_MFRMS) TDMA FN Space 0 ~24.5 seconds 104 512 1 ~49 seconds208 256 2 ~1.63 minutes 416 128 3 ~3.25 minutes 832 64 4 ~6.5 minutes1664 32 5 ~13 minutes 3328 16 6 ~26 minutes 6656 8 7 ~52 minutes 13312 4Note 1: 53248 51-multiframes occur with the TDMA FN space (2715648 TDMAframes) Note 2: All remaining EXTENDED_DRX values are reserved

Example

-   -   IMSI=00000000 01001001 00110000 00000001=4796417 and        EXTENDED_DRX_MFRMS=6656 (i.e., the eDRX cycle˜26 minutes)    -   N=16*6656=106496.    -   CC1 Nominal Paging Group=mod (IMSI, 106496)=4097 which occurs in        the 4098^(th) EC-PCH block of the eDRX cycle (i.e., in the        2^(nd) EC-PCH block in 51-multiframe #257.    -   The nominal paging groups associated with other DL CC for the        same IMSI and eDRX cycle length are as shown in FIG. 6.2.4.3-1        (e.g., the nominal paging group for DL CC 2 occurs in the 1^(st)        and 2^(nd) EC-PCH blocks of 51-multiframe #257).

As can be seen in FIG. 5 (GP-150133's FIG. 1—Cover Class Specific PagingGroups), using this method for establishing DL CC specific nominalpaging groups for a given eDRX cycle ensures that for a given IMSI thenominal paging groups associated with all possible DL CC will fallwithin 4 51-multiframes of the EC-PCH CC1 block. As such, if a wirelessdevice 104 ₂ (for example) sends a CC update to the CN node 107 (e.g.,SGSN 107) (e.g., using a Cell Update) e.g., 5 seconds prior to the nextoccurrence of its nominal paging group, the RAN node 102 ₂ (e.g., BSS102 ₂) will still be able to send a page in time for it to be receivedby the device monitoring according to its DL CC incremented by 1 level.With the ability to update its DL CC as late as a few seconds before thenext occurrence of its nominal paging group, a device will therebyexperience a substantially reduced probability of missing a page due toit having to select a higher downlink coverage class shortly before itsnext paging opportunity (i.e., shortly before the next instance of itsnominal paging group).

It should be understood that a RAN node 102 ₂ (for example) always hasprecise knowledge of the ongoing transmission of specific TDMA framesover the radio interface corresponding to each of the set of cells itmanages. As such, once the RAN node 102 ₂ determines the nominal paginggroup of a wireless device 104 ₂ (for example) it can calculate the timeremaining until the next paging opportunity 156 for that wireless device104 ₂. It should also be appreciated that there are other ways inaddition to the one described herein as disclosed in GP-150133 andGP-150259 that the RAN node 102 ₂ can use to calculate the timeremaining until the next paging opportunity 156.

Basic Functionalities-Configurations of CN Node 107 and RAN Node 102 ₂(for Example)

Referring to FIG. 6, there is a flowchart of a method 600 implemented inthe CN node 107 (e.g., SGSN 107) which interacts with RAN nodes 102 ₁and 102 ₂ (BSS 102 ₁ and 102 ₂) to time coordinate cells 152 ₁ and 152 ₂and maintain a reliability of paging a wireless device 104 ₂ (forexample) in accordance with an embodiment of the present disclosure. Atstep 602, the CN node 107 obtains, from one of the RAN nodes 102 ₁ or102 ₂, information indicating a time remaining until a next pagingopportunity 156 for the wireless device 104 ₂ within the cells 152 ₁ and152 ₂ comprising a paging area 154 of the wireless device 104 ₂. Severalexamples of how the CN node 107 can obtain the time remaining until anext paging opportunity 156 for the wireless device 104 ₂ are asfollows:

1. The CN node 107 can per step 602 obtain from one of the RAN nodes 102₁ or 102 ₂, the time remaining until a next paging opportunity 156 by:(1) receiving a first BSSGP PDU 204 containing a RAU Request from oneRAN node 102 ₂ (for example), wherein the RAU Request is associated withthe wireless device 104 ₂ (step 602 a 1); (2) transmitting a secondBSSGP PDU 206 containing a RAU Accept to the one RAN node 102 ₂, whereinthe second BSSGP PDU 206 includes TLLI parameters (e.g., IMSI, eDRXcycle length, coverage class (not applicable for uPoD devices))associated with the wireless device 104 ₂ (step 602 a 2); and (3)receiving a third BSSGP PDU 212 containing a RAU Complete from the oneRAN node 102 ₂, wherein the third BSSGP PDU 212 includes the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ (step 602 a 3). See also FIG. 2 and its associated text foranother discussion about this exemplary way that the CN node 107 canobtain the time remaining until a next paging opportunity 156 for thewireless device 104 ₂.

2. The CN node 107 can per step 602 obtain from one of the RAN nodes 102₁ or 102 ₂, the time remaining until a next paging opportunity 156 by:(1) transmitting a paging request 302 to the one RAN node 102 ₂ (forexample), wherein the paging request 302 includes TLLI parameters (e.g.,IMSI, eDRX cycle length, coverage class (not applicable for uPoDdevices)) associated with the wireless device 104 ₂ (step 602 b 1); and(2) receiving a paging response 308 from the one RAN node 102 ₂, whereinthe paging response 308 includes the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂ (step 602 b 2). See alsoFIG. 3 and its associated text for another discussion about thisexemplary way that the CN node 107 can obtain the time remaining until anext paging opportunity 156 for the wireless device 104 ₂.

3. The CN node 107 can per step 602 obtain from one of the RAN nodes 102₁ or 102 ₂, the time remaining until a next paging opportunity 156 by:(1) transmitting a dummy paging request 402 to the one RAN node 102 ₂(for example), wherein the dummy paging request 402 includes TLLIparameters (e.g., IMSI, eDRX cycle length, coverage class (notapplicable for uPoD devices)) associated with the wireless device 104 ₂(step 602 c 1); and (2) receiving a dummy paging response 404 from theone RAN node 102 ₂, wherein the dummy paging response 404 includes thetime remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂ (step 602 c 2) (note: the dummy paging response 404corresponds to the dummy paging request 402, i.e., when a given dummypaging response 404 is received it always corresponds to one specificpreviously transmitted dummy paging request 402). See also FIG. 4 andits associated text for another discussion about this exemplary way thatthe CN node 107 can obtain the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂. Recall in this case theRAN node 102 ₂ does not transmit a paging message over a radio interfaceto the wireless device 104 ₂, and the CN node 107 can send the dummypaging request 402 as frequently as it desires to verify itsunderstanding of when the next paging opportunity will occur for a givenwireless device 104 ₂ (for example).

At step 604, the CN node 107 maintains an eDRX cycle timer 158associated with the wireless device 104 ₂ by using the obtained timeremaining until the next paging opportunity 156 for the wireless device104 ₂ and an eDRX cycle length associated with the wireless device 104₂. For example, the CN node 107 can maintain the eDRX cycle timer 158by: (1) obtaining updated information indicating the time remaininguntil the next paging opportunity 156 for the wireless device 104 ₂(step 604 a) (note: the updated information can be obtained asfrequently or infrequently as desired by the CN node 107); and (2)modifying the eDRX cycle timer 158 based on the obtained updatedinformation indicating the time remaining until the next pagingopportunity 156 for the wireless device 104 ₂ (step 604 b). At step 606,the CN node 107 sets the eDRX cycle timer 158 to expire a predeterminedtime (e.g., few seconds) before the next paging opportunity for thewireless device 104 ₂. Upon the expiration of the eDRX cycle timer 158and based on there being a buffered paging message for the wirelessdevice 104 ₂, the CN node 107 at step 608 transmits a set of pagingrequests to the RAN nodes 102 ₁ and 102 ₂ managing the cells 152 ₁ and152 ₂ comprising the paging area 154 of the wireless device 104 ₂ andrestarts the eDRX cycle timer 158 (recall: the CN node 107 will buffer apaging message for the wireless device 104 ₂ upon receiving a N-PDU forthe wireless device 104 ₂). Upon the expiration of the eDRX cycle timer158 and based on there being no buffered paging message for the wirelessdevice 104 ₂, the CN node 107 at step 610 restarts the eDRX cycle timer158.

Referring to FIG. 7, there is a block diagram illustrating structures ofan exemplary CN node 107 (e.g., SGSN 107) which interacts with RAN nodes102 ₁ and 102 ₂ (BSS 102 ₁ and 102 ₂) to time coordinate cells 152 ₁ and152 ₂ and maintain a reliability of paging a wireless device 104 ₂ (forexample) in accordance with an embodiment of the present disclosure. Inone embodiment, the CN node 107 comprises an obtain module 702, amaintain module 704, a set module 706, a transmit-restart module 708,and a restart module 710. The obtain module 702 is configured to obtain,from one of the RAN nodes 102 ₁ or 102 ₂, information indicating a timeremaining until a next paging opportunity 156 for the wireless device104 ₂ within the cells 152 ₁ and 152 ₂ comprising a paging area 154 ofthe wireless device 104 ₂. Several examples of how the obtain module 702can be configured to obtain the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂ are as follows:

1. The obtain module 702 can obtain from one of the RAN nodes 102 ₁ or102 ₂, the time remaining until a next paging opportunity 156 by: (1)receiving a first BSSGP PDU 204 containing a RAU Request from one RANnode 102 ₂ (for example), wherein the RAU Request is associated with thewireless device 104 ₂ (first receive module 702 a 1); (2) transmitting asecond BSSGP PDU 206 containing a RAU Accept to the one RAN node 102 ₂,wherein the second BSSGP PDU 206 includes TLLI parameters (e.g., IMSI,eDRX cycle length, coverage class (not applicable for uPoD devices))associated with the wireless device 104 ₂ (transmit module 702 a 2); and(3) receiving a third BSSGP PDU 212 containing a RAU Complete from theone RAN node 102 ₂, wherein the third BSSGP PDU 212 includes the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ (second receive module 702 a 3). See also FIG. 2 and itsassociated text for another discussion about this exemplary way that theobtain module 702 can obtain the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂.

2. The obtain module 702 can obtain from one of the RAN nodes 102 ₁ or102 ₂, the time remaining until a next paging opportunity 156 by: (1)transmitting a paging request 302 to the one RAN node 102 ₂ (forexample), wherein the paging request 302 includes TLLI parameters (e.g.,IMSI, eDRX cycle length, coverage class (not applicable for uPoDdevices)) associated with the wireless device 104 ₂ (transmit module 702b 1); and (2) receiving a paging response 308 from the one RAN node 102₂, wherein the paging response 308 includes the time remaining until anext paging opportunity 156 for the wireless device 104 ₂ (receivemodule 702 b 2). See also FIG. 3 and its associated text for anotherdiscussion about this exemplary way that the obtain module 702 canobtain the time remaining until a next paging opportunity 156 for thewireless device 104 ₂.

3. The obtain module 702 can obtain from one of the RAN nodes 102 ₁ or102 ₂, the time remaining until a next paging opportunity 156 by: (1)transmitting a dummy paging request 402 to the one RAN node 102 ₂ (forexample), wherein the dummy paging request 402 includes TLLI parameters(e.g., IMSI, eDRX cycle length, coverage class (not applicable for uPoDdevices)) associated with the wireless device 104 ₂ (transmit module 702c 1); and (2) receiving a dummy paging response 404 from the one RANnode 102 ₂, wherein the dummy paging response 404 includes the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ (receive module 702 c 2) (note: the dummy paging response 404corresponds to the dummy paging request 402, i.e., when a given dummypaging response 404 is received it always corresponds to one specificpreviously transmitted dummy paging request 402). See also FIG. 4 andits associated text for another discussion about this exemplary way thatthe obtain module 702 can obtain the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂. Recall in this case theRAN node 102 ₂ does not transmit a paging message over a radio interfaceto the wireless device 104 ₂, and the CN node 107 can send the dummypaging request 402 as frequently as it desires to verify itsunderstanding of when the next paging opportunity will occur for a givenwireless device 104 ₂ (for example).

The maintain module 704 is configured to maintain an eDRX cycle timer158 associated with the wireless device 104 ₂ by using the obtained timeremaining until the next paging opportunity 156 for the wireless device104 ₂ and an eDRX cycle length associated with the wireless device 104₂. For example, the maintain module 704 can maintain the eDRX cycletimer 158 by: (1) obtaining updated information indicating the timeremaining until the next paging opportunity 156 for the wireless device104 ₂ (note: the updated information can be obtained as frequently orinfrequently as desired by the maintain module 704); and (2) modifyingthe eDRX cycle timer 158 based on the obtained updated informationindicating the time remaining until the next paging opportunity 156 forthe wireless device 104 ₂. The set module 706 is configured to set theeDRX cycle timer 158 to expire a predetermined time (e.g., few seconds)before the next paging opportunity for the wireless device 104 ₂. Uponthe expiration of the eDRX cycle timer 158 and based on there being abuffered paging message for the wireless device 104 ₂, thetransmit-restart module 708 is configured to transmit a set of pagingrequests to the RAN nodes 102 ₁ and 102 ₂ managing the cells 152 ₁ and152 ₂ comprising the paging area 154 of the wireless device 104 ₂ andrestart the eDRX cycle timer 158 (recall: the CN node 107 will buffer apaging message for the wireless device 104 ₂ upon receiving a N-PDU forthe wireless device 104 ₂). Upon the expiration of the eDRX cycle timer158 and based on there being no buffered paging message for the wirelessdevice 104 ₂, the restart module 710 is configured to restart the eDRXcycle timer 158. Further, it should be noted that the CN node 107 mayalso include other components, modules or structures which arewell-known, but for clarity, only the components, modules or structuresneeded to describe the features of the present disclosure are describedherein.

As those skilled in the art will appreciate, the above-described modules702, 704, 706, 708, and 710 of the CN node 107 may be implementedseparately as suitable dedicated circuits. Further, the modules 702,704, 706, 708, and 710 can also be implemented using any number ofdedicated circuits through functional combination or separation. In someembodiments, the modules 702, 704, 706, 708, and 710 may be evencombined in a single application specific integrated circuit (ASIC). Asan alternative software-based implementation, the CN node 107 maycomprise a memory 148, a processor 146 (including but not limited to amicroprocessor, a microcontroller or a Digital Signal Processor (DSP),etc.) and a transceiver 136. The memory 148 stores machine-readableprogram code executable by the processor 146 to cause the CN node 107 toperform the steps of the above-described method 600.

Referring to FIG. 8, there is a flowchart of a method 800 implemented inthe CN node 107 (e.g., SGSN 107) in accordance with an embodiment of thepresent disclosure. At step 802, the CN node 107 sends, to a RAN node102 ₂ (for example), a dummy paging request 402 associated with awireless device 104 ₂ (for example). The dummy paging request 402includes TLLI specific parameters (e.g., IMSI, eDRX cycle length,coverage class (not applicable for uPoD devices)) associated with thewireless device 104 ₂. Further, the dummy paging request 402 is definedto trigger the RAN node 102 ₂ (e.g., BSS 102 ₂) to calculate the timeremaining until the next paging opportunity 156 for the wireless device104 ₂ within the cells 152 ₁ and 152 ₂ comprising a paging area 154 ofthe wireless device 104 ₂. In this case, the RAN node 102 ₂ (e.g., BSS102 ₂) upon receiving the dummy paging request 402 does not send apaging message over the radio interface to the wireless device 104 ₂. Atstep 804, the CN node 107 receives, from the RAN node 102 ₂ (e.g., BSS102 ₂), a dummy paging response 404 which includes a time remaininguntil a next paging opportunity 156 for the wireless device 104 ₂ (note:the dummy paging response 404 corresponds to the dummy paging request402, i.e., when a given dummy paging response 404 is received it alwayscorresponds to one specific previously transmitted dummy paging request402). At step 806, the CN node 107 maintains an eDRX cycle timer 158associated with the wireless device 104 ₂ by using the obtained timeremaining until the next paging opportunity 156 for the wireless device104 ₂ and an eDRX cycle length associated with the wireless device 104₂. For example, the CN node 107 can maintain the eDRX cycle timer 158by: (1) sending a dummy paging request to the RAN node 102 ₂ (e.g., BSS102 ₂) as frequently or infrequently as desired to obtain updated timeremaining until the next paging opportunity 156 for the wireless device104 ₂ (step 806 a); and (2) modifying the eDRX cycle timer 158 based onthe obtained updated information indicating the time remaining until thenext paging opportunity 156 for the wireless device 104 ₂ (step 806 b).At step 808, the CN node 107 sets the eDRX cycle timer 158 to expire apredetermined time (e.g., few seconds) before the next pagingopportunity for the wireless device 104 ₂. Upon the expiration of theeDRX cycle timer 158 and based on there being a buffered paging messagefor the wireless device 104 ₂, the CN node 107 at step 810 transmits aset of paging requests to the RAN nodes 102 ₁ and 102 ₂ which aremanaging the cells 152 ₁ and 152 ₂ comprising the paging area 154 of thewireless device 104 ₂ and restarts the eDRX cycle timer 158 (recall: theCN node 107 will buffer a paging message for the wireless device 104 ₂upon receiving a N-PDU for the wireless device 104 ₂). Upon theexpiration of the eDRX cycle timer 158 and based on there being nobuffered paging message for the wireless device 104 ₂, the CN node 107at step 812 restarts the eDRX cycle timer 158.

Referring to FIG. 9, there is a block diagram illustrating structures ofan exemplary CN node 107 (e.g., SGSN 107) configured in accordance withan embodiment of the present disclosure. In one embodiment, the CN node107 comprises a send module 902, a receive module 904, a maintain module906, a set module 908, a transmit-restart module 910, and a restartmodule 912. The send module 902 is configured to send, to a RAN node 102₂ (for example), a dummy paging request 402 associated with a wirelessdevice 104 ₂ (for example). The dummy paging request 402 can includeTLLI specific parameters (e.g., IMSI, eDRX cycle length, coverage class(not applicable for uPoD devices)) associated with the wireless device104 ₂. Further, the dummy paging request 402 is defined to trigger theRAN node 102 ₂ (e.g., BSS 102 ₂) to calculate the time remaining untilthe next paging opportunity 156 for the wireless device 104 ₂ within thecells 152 ₁ and 152 ₂ comprising a paging area 154 of the wirelessdevice 104 ₂. In this case, the RAN node 102 ₂ (e.g., BSS 102 ₂) uponreceiving the dummy paging request 402 does not send a paging messageover the radio interface to the wireless device 104 ₂. The receivemodule 904 is configured to receive, from the RAN node 102 ₂ (e.g., BSS102 ₂), a dummy paging response 404 which includes a time remaininguntil a next paging opportunity 156 for the wireless device 104 ₂ (note:the dummy paging response 404 corresponds to the dummy paging request402, i.e., when a given dummy paging response 404 is received it alwayscorresponds to one specific previously transmitted dummy paging request402). The maintain module 906 is configured to maintain an eDRX cycletimer 158 associated with the wireless device 104 ₂ by using theobtained time remaining until the next paging opportunity 156 for thewireless device 104 ₂ and an eDRX cycle length associated with thewireless device 104 ₂. For example, the maintain module 906 can maintainthe eDRX cycle timer 158 by: (1) sending a dummy paging request 402 tothe RAN node 102 ₂ (e.g., BSS 102 ₂) as frequently or infrequently asdesired to obtain updated time remaining until the next pagingopportunity 156 for the wireless device 104 ₂; and (2) modifying theeDRX cycle timer 158 based on the obtained updated informationindicating the time remaining until the next paging opportunity 156 forthe wireless device 104 ₂. The set module 908 is configured to set theeDRX cycle timer 158 to expire a predetermined time (e.g., few seconds)before the next paging opportunity for the wireless device 104 ₂. Uponthe expiration of the eDRX cycle timer 158 and based on there being abuffered paging message for the wireless device 104 ₂, thetransmit-restart module 910 is configured to transmit a set of pagingrequests to the RAN nodes 102 ₁ and 102 ₂ which are managing the cells152 ₁ and 152 ₂ comprising the paging area 154 of the wireless device104 ₂ and restart the eDRX cycle timer 158 (recall: the CN node 107 willbuffer a paging message for the wireless device 104 ₂ upon receiving aN-PDU for the wireless device 104 ₂). Upon the expiration of the eDRXcycle timer 158 and based on there being no buffered paging message forthe wireless device 104 ₂, the restart module 912 is configured torestart the eDRX cycle timer 158. Further, it should be noted that theCN node 107 may also include other components, modules or structureswhich are well-known, but for clarity, only the components, modules orstructures needed to describe the features of the present disclosure aredescribed herein.

As those skilled in the art will appreciate, the above-described modules902, 904, 906, 908, 910, and 912 of the CN node 107 may be implementedseparately as suitable dedicated circuits. Further, the modules 902,904, 906, 908, 910, and 912 can also be implemented using any number ofdedicated circuits through functional combination or separation. In someembodiments, the modules 902, 904, 906, 908, 910, and 912 may be evencombined in a single application specific integrated circuit (ASIC). Asan alternative software-based implementation, the CN node 107 maycomprise a memory 148, a processor 146 (including but not limited to amicroprocessor, a microcontroller or a Digital Signal Processor (DSP),etc.) and a transceiver 136. The memory 148 stores machine-readableprogram code executable by the processor 146 to cause the CN node 107 toperform the steps of the above-described method 800.

Referring to FIG. 10, there is a flowchart of a method 1000 implementedin the RAN node 102 ₂ (BSS 102 ₂) which interacts with the CN node 107(e.g., SGSN 107) to time coordinate cells 152 ₁ and 152 ₂ and maintain areliability of paging a wireless device 104 ₂ (for example) inaccordance with an embodiment of the present disclosure. At step 1002,the RAN node 102 ₂ provides, to the CN node 107, information indicatinga time remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂ within the cells 152 ₁ and 152 ₂ comprising a paging area154 of the wireless device 104 ₂. Several examples of how the RAN node102 ₂ can provide the time remaining until a next paging opportunity 156for the wireless device 104 ₂ are as follows:

1. The RAN node 102 ₂ can per step 1002 provide the CN node 107 with thetime remaining until a next paging opportunity 156 by: (1) transmittinga first BSSGP PDU 204 containing a RAU Request to the CN node 107,wherein the RAU Request is associated with the wireless device 104 ₂(step 1002 a 1); (2) receiving a second BSSGP PDU 206 containing a RAUAccept from the CN node 107, wherein the second BSSGP PDU 206 includesTLLI parameters (e.g., IMSI, eDRX cycle length, coverage class (notapplicable for uPoD devices)) associated with the wireless device 104 ₂(step 1002 a 2); (3) calculating the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂ using at least the TLLIparameters (e.g., IMSI, eDRX cycle length, coverage class (notapplicable for uPoD devices)) associated with the wireless device 104 ₂(step 1002 a 3) (e.g., see description associated with TABLE 1 and FIG.5); and (4) transmitting a third BSSGP PDU 212 containing a RAU Completeto the CN node 107, wherein the third BSSGP PDU 212 includes the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ (step 1002 a 4). See also FIG. 2 and its associated text foranother discussion about this exemplary way that the RAN node 102 ₂ canprovide the CN node 107 with the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂.

2. The RAN node 102 ₂ can per step 1002 provide the CN node 107 with thetime remaining until a next paging opportunity 156 by: (1) receiving apaging request 302 from the CN node 107, wherein the paging request 302includes TLLI parameters (e.g., IMSI, eDRX cycle length, coverage class(not applicable for uPoD devices)) associated with the wireless device104 ₂ (step 1002 b 1); (2) transmitting a paging message 304 to thewireless device 104 ₂ (step 1002 b 2); (3) receiving a first pagingresponse 306 from the wireless device 104 ₂ (step 1002 b 3); (4)calculating the time remaining until a next paging opportunity 156 forthe wireless device 104 ₂ using at least the TLLI parameters (e.g.,IMSI, eDRX cycle length, coverage class (not applicable for uPoDdevices)) associated with the wireless device 104 ₂ (step 1002 b 4)(e.g., see description associated with TABLE 1 and FIG. 5); and (5)transmitting a second paging response 308 to the CN node 107, whereinthe second paging response 308 includes the time remaining until a nextpaging opportunity 156 for the wireless device 104 ₂ (step 1002 b 5).See also FIG. 3 and its associated text for another discussion aboutthis exemplary way that the RAN node 102 ₂ can provide the CN node 107with the time remaining until a next paging opportunity 156 for thewireless device 104 ₂.

3. The RAN node 102 ₂ can per step 1002 provide the CN node 107 with thetime remaining until a next paging opportunity 156 by: (1) receiving adummy paging request 402 from the CN node 107, wherein the dummy pagingrequest 402 includes TLLI parameters (e.g., IMSI, eDRX cycle length,coverage class (not applicable for uPoD devices)) associated with thewireless device 104 ₂ (step 1002 c 1); (2) upon receiving the dummypaging request 402 do not transmit a paging message over the radiointerface to the wireless device 104 ₂ but instead calculate the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ using at least the TLLI parameters (e.g., IMSI, eDRX cycle length,coverage class (not applicable for uPoD devices)) associated with thewireless device 104 ₂ (step 1002 c 2) (e.g., see description associatedwith TABLE 1 and FIG. 5); and (3) transmitting a dummy paging response404 to the CN node 107, wherein the dummy paging response includes thetime remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂ (step 1002 c 3) (note: the dummy paging response 404corresponds to the dummy paging request 402, i.e., when a given dummypaging response 404 is received it always corresponds to one specificpreviously transmitted dummy paging request 402). See also FIG. 4 andits associated text for another discussion about this exemplary way thatthe RAN node 102 ₂ can provide the CN node 107 with the time remaininguntil a next paging opportunity 156 for the wireless device 104 ₂.Recall in this case the CN node 107 can send the dummy paging request402 as frequently as it desires to verify its understanding of when thenext paging opportunity will occur for a given wireless device 104 ₂(for example).

Referring to FIG. 11, there is a block diagram illustrating structuresof an exemplary RAN node 102 ₂ (for example) configured to interact withthe CN node 107 (e.g., SGSN 107) to time coordinate cells 152 ₁ and 152₂ and maintain a reliability of paging a wireless device 104 ₂ (forexample) in accordance with an embodiment of the present disclosure. Inone embodiment, the RAN node 102 ₂ comprises a provide module 110 ₂. Theprovide module 110 ₂ is configured to provide, to the CN node 107,information indicating a time remaining until a next paging opportunity156 for the wireless device 104 ₂ within the cells 152 ₁ and 152 ₂comprising a paging area 154 of the wireless device 104 ₂. Severalexamples of how the provide module 110 ₂ can provide the time remaininguntil a next paging opportunity 156 for the wireless device 104 ₂ are asfollows:

1. The provide module 110 ₂ can be configured to provide the CN node 107with the time remaining until a next paging opportunity 156 by: (1)transmitting a first BSSGP PDU 204 containing a RAU Request to the CNnode 107, wherein the RAU Request is associated with the wireless device104 ₂ (first transmit module 1102 a 1); (2) receiving a second BSSGP PDU206 containing a RAU Accept from the CN node 107, wherein the secondBSSGP PDU 206 includes TLLI parameters (e.g., IMSI, eDRX cycle length,coverage class (not applicable for uPoD devices)) associated with thewireless device 104 ₂ (receive module 1102 a 2); (3) calculating thetime remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂ using at least the TLLI parameters (e.g., IMSI, eDRX cyclelength, coverage class (not applicable for uPoD devices)) associatedwith the wireless device 104 ₂ (calculate module 1102 a 3) (e.g., seedescription associated with TABLE 1 and FIG. 5); and (4) transmitting athird BSSGP PDU 212 containing a RAU Complete to the CN node 107,wherein the third BSSGP PDU 212 includes the time remaining until a nextpaging opportunity 156 for the wireless device 104 ₂ (second transmitmodule 1102 a 4). See also FIG. 2 and its associated text for anotherdiscussion about this exemplary way that the RAN node 102 ₂ can providethe CN node 107 with the time remaining until a next paging opportunity156 for the wireless device 104 ₂.

2. The provide module 110 ₂ can be configured to provide the CN node 107with the time remaining until a next paging opportunity 156 by: (1)receiving a paging request 302 from the CN node 107, wherein the pagingrequest 302 includes TLLI parameters (e.g., IMSI, eDRX cycle length,coverage class (not applicable for uPoD devices)) associated with thewireless device 104 ₂ (first receive module 1102 b 1); (2) transmittinga paging message 304 to the wireless device 104 ₂ (first transmit module1002 b 2); (3) receiving a first paging response 306 from the wirelessdevice 104 ₂ (second receive module 1102 b 3); (4) calculating the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ using at least the TLLI parameters (e.g., IMSI, eDRX cycle length,coverage class (not applicable for uPoD devices)) associated with thewireless device 104 ₂ (calculate module 1102 b 4) (e.g., see descriptionassociated with TABLE 1 and FIG. 5); and (5) transmitting a secondpaging response 308 to the CN node 107, wherein the second pagingresponse 308 includes the time remaining until a next paging opportunity156 for the wireless device 104 ₂ (second transmit module 1102 b 5). Seealso FIG. 3 and its associated text for another discussion about thisexemplary way that the RAN node 102 ₂ can provide the CN node 107 withthe time remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂.

3. The provide module 110 ₂ can be configured to provide the CN node 107with the time remaining until a next paging opportunity 156 by: (1)receiving a dummy paging request 402 from the CN node 107, wherein thedummy paging request 402 includes TLLI parameters (e.g., IMSI, eDRXcycle length, coverage class (not applicable for uPoD devices))associated with the wireless device 104 ₂ (receive module 1102 c 1); (2)upon receiving the dummy paging request 402 do not transmit a pagingmessage over the radio interface to the wireless device 104 ₂ butinstead calculate the time remaining until a next paging opportunity 156for the wireless device 104 ₂ using at least the TLLI parameters (e.g.,IMSI, eDRX cycle length, coverage class (not applicable for uPoDdevices)) associated with the wireless device 104 ₂ (calculate module1102 c 2) (e.g., see description associated with TABLE 1 and FIG. 5);and (3) transmitting a dummy paging response 404 to the

CN node 107, wherein the dummy paging response 404 includes the timeremaining until a next paging opportunity 156 for the wireless device104 ₂ (transmit module 1102 c 3) (note: the dummy paging response 404corresponds to the dummy paging request 402, i.e., when a given dummypaging response 404 is received it always corresponds to one specificpreviously transmitted dummy paging request 402). See also FIG. 4 andits associated text for another discussion about this exemplary way thatthe RAN node 102 ₂ can provide the CN node 107 with the time remaininguntil a next paging opportunity 156 for the wireless device 104 ₂.Recall in this case the CN node 107 can send the dummy paging request402 as frequently as it desires to verify its understanding of when thenext paging opportunity will occur for a given wireless device 104 ₂(for example). It should be noted that the RAN node 102 ₂ may alsoinclude other components, modules or structures which are well-known,but for clarity, only the components, modules or structures needed todescribe the features of the present disclosure are described herein.The other RAN node 102 ₁ can also be configured in a similar manner withthe illustrated structure of the RAN node 102 ₂.

As those skilled in the art will appreciate, the above-described module110 ₂ of the RAN node 102 ₂ (e.g., BSS 102 ₂, NodeB 102 ₂, eNodeB 102 ₂)may be implemented by suitable dedicated circuit(s). Further, the module110 ₂ can also be implemented using any number of dedicated circuitsthrough functional combination or separation. In some embodiments, themodule 110 ₂ may be even combined in a single application specificintegrated circuit (ASIC). As an alternative software-basedimplementation, the RAN node 102 ₂ may comprise a memory 134 ₂, aprocessor 132 ₂ (including but not limited to a microprocessor, amicrocontroller or a Digital Signal Processor (DSP), etc.) and atransceiver 122 ₂. The memory 134 ₂ stores machine-readable program codeexecutable by the processor 132 ₂ to cause the RAN node 102 ₂ (e.g., BSS102 ₂, NodeB 102 ₂, eNodeB 102 ₂) to perform the steps of theabove-described method 1000. It should be appreciated that the other RANnodes 102 ₁ (for example) can also be configured in a similar manner asthe RAN node 102 ₂ to perform method 1000.

Referring to FIG. 12, there is a flowchart of a method 1200 implementedin the RAN node 102 ₂ (BSS 102 ₂) in accordance with an embodiment ofthe present disclosure. At step 1202, the RAN node 102 ₂ receives, fromthe CN node 107, a dummy paging request 402 associated with a wirelessdevice 104 ₂ (for example). The dummy paging request 402 can includeTLLI parameters (e.g., IMSI, eDRX cycle length, coverage class (notapplicable for uPoD devices)) associated with the wireless device 104 ₂.At step 1204, the RAN node 102 ₂ uses information (e.g., TLLIparameters) provided within the dummy paging request 402 to calculatethe time remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂ (e.g., see description associated with TABLE 1 and FIG. 5).The RAN node 102 ₂ upon receiving the dummy paging request 402 does nottransmit a paging message over the radio interface to the wirelessdevice 104 ₂ but instead calculates the time remaining until a nextpaging opportunity 156 for the wireless device 104 ₂ using at least theTLLI parameters (e.g., IMSI, eDRX cycle length, coverage class (notapplicable for uPoD devices)) associated with the wireless device 104 ₂.At step 120 ₆, the RAN node 102 ₂ transmits a dummy paging response 404to the CN node 107, wherein the dummy paging response 404 includes thetime remaining until a next paging opportunity 156 for the wirelessdevice 104 ₂ (note: the dummy paging response 404 corresponds to thedummy paging request 402, i.e., when a given dummy paging response 404is received it always corresponds to one specific previously transmitteddummy paging request 402). See also FIG. 4 and its associated text foranother discussion about this exemplary way that the RAN node 102 ₂ canprovide the CN node 107 with the time remaining until a next pagingopportunity 156 for the wireless device 104 ₂. Recall in this case theCN node 107 can send the dummy paging request 402 as frequently as itdesires to verify its understanding of when the next paging opportunitywill occur for a given wireless device 104 ₂ (for example).

Referring to FIG. 13, there is a block diagram illustrating structuresof an exemplary RAN node 102 ₂ (for example) configured in accordancewith an embodiment of the present disclosure. In one embodiment, the RANnode 102 ₂ comprises a receive module 130 ₂, a use module 130 ₄, and atransmit module 130 ₆. The receive module 130 ₂ is configured toreceive, from the CN node 107, a dummy paging request 402 associatedwith a wireless device 104 ₂ (for example). The dummy paging request 402can include TLLI parameters (e.g., IMSI, eDRX cycle length, coverageclass (not applicable for uPoD devices)) associated with the wirelessdevice 104 ₂. The use module 130 ₄ is configured to use information(e.g., TLLI parameters) provided within the dummy paging request 402 tocalculate the time remaining until a next paging opportunity 156 for thewireless device 104 ₂ (e.g., see description associated with TABLE 1 andFIG. 5). The use module 130 ₄ upon receiving the dummy paging request402 does not transmit a paging message over the radio interface to thewireless device 104 ₂ but instead calculates the time remaining until anext paging opportunity 156 for the wireless device 104 ₂ using at leastthe TLLI parameters (e.g., IMSI, eDRX cycle length, coverage class (notapplicable for uPoD devices)) associated with the wireless device 104 ₂.The transmit module 130 ₆ is configured to transmit a dummy pagingresponse 404 to the CN node 107, wherein the dummy paging response 404includes the time remaining until a next paging opportunity 156 for thewireless device 104 ₂ (note: the dummy paging response 404 correspondsto the dummy paging request 402, i.e., when a given dummy pagingresponse 404 is received it always corresponds to one specificpreviously transmitted dummy paging request 402). It should be notedthat the RAN node 102 ₂ may also include other components, modules orstructures which are well-known, but for clarity, only the components,modules or structures needed to describe the features of the presentdisclosure are described herein. The other RAN node 102 ₁ can also beconfigured in a similar manner with the illustrated structure of the RANnode 102 ₂.

As those skilled in the art will appreciate, the above-described modules130 ₂, 130 ₄, and 130 ₆ of the RAN node 102 ₂ (e.g., BSS 102 ₂, NodeB102 ₂, eNodeB 102 ₂) may be implemented by suitable dedicated circuits.Further, the modules 130 ₂, 130 ₄, and 130 ₆ can also be implementedusing any number of dedicated circuits through functional combination orseparation. In some embodiments, the modules 130 ₂, 130 ₄, and 130 ₆ maybe even combined in a single application specific integrated circuit(ASIC). As an alternative software-based implementation, the RAN node102 ₂ may comprise a memory 134 ₂, a processor 132 ₂ (including but notlimited to a microprocessor, a microcontroller or a Digital SignalProcessor (DSP), etc.) and a transceiver 122 ₂. The memory 134 ₂ storesmachine-readable program code executable by the processor 132 ₂ to causethe RAN node 102 ₂ (e.g., BSS 102 ₂, NodeB 102 ₂, eNodeB 102 ₂) toperform the steps of the above-described method 120 ₀. It should beappreciated that the other RAN nodes 102 ₁ (for example) can also beconfigured in a similar manner as the RAN node 102 ₂ to perform method1200.

In view of the foregoing, one skilled in the art will appreciate thatthe present disclosure discloses a CN node 107 (e.g., SGSN 107), RANnodes 102 ₁ and 102 ₂ (e.g., BSS 102 ₁ and 102 ₂), and various methods600, 800, 1000 and 1200 that address the drawbacks of thestate-of-the-art by realizing time coordinated cells 152 ₁ and 152 ₂ andmaintaining a reliability of paging a wireless device 104 ₂ (e.g., MTCdevice 104 ₂, mobile station 104 ₂). The present disclosure has severaladvantages some of which are as follows: the techniques of realizingtime coordinated cells described herein allows for maintaining areliability of paging for wireless devices using eDRX cycle lengths thatis equivalent to that associated with wireless devices using legacy DXRcycle lengths. In addition, the techniques of providing a CN node (e.g.,SGSN) with information about “time remaining until the next pagingopportunity” for wireless devices described herein may be seen asrelatively less complex and inexpensive compared to solutions that relyon (a) the CN node (e.g., SGSN) needing to know about the radiointerface related frame structures used to determine exact pagingoccasions, or (b) the wireless devices being equipped with GPS receiversfor conveying precise time of day information to the CN node (e.g.,SGSN).

The techniques described herein are applicable to any Radio AccessTechnology (RAT), wherein the controlling core network node (e.g., SGSN,Mobility Management Entity (MME), or similar) needs to know when thepaging opportunity occurs on the radio interface, wherein the RAN (e.g.,Base Station System (BSS), Node B (Nb), evolved Nb (eNb), or similar),during active data transfer, provides the controlling core network nodeswith timing information of the radio interface, and/or wherein theinformation to calculate the radio interface timing is provided by thecontrolling core network node. It is further to be noted that theinformation needed to determine the radio interface timing may vary fromsystem to system, and thus, may be solution dependent.

Those skilled in the art will appreciate that the use of the term“exemplary” is used herein to mean “illustrative,” or “serving as anexample,” and is not intended to imply that a particular embodiment ispreferred over another or that a particular feature is essential.Likewise, the terms “first” and “second,” and similar terms, are usedsimply to distinguish one particular instance of an item or feature fromanother, and do not indicate a particular order or arrangement, unlessthe context clearly indicates otherwise. Further, the term “step,” asused herein, is meant to be synonymous with “operation” or “action.” Anydescription herein of a sequence of steps does not imply that theseoperations must be carried out in a particular order, or even that theseoperations are carried out in any order at all, unless the context orthe details of the described operation clearly indicates otherwise.

Of course, the present disclosure may be carried out in other specificways than those herein set forth without departing from the scope andessential characteristics of the invention. One or more of the specificprocesses discussed above may be carried out in a cellular phone orother communications transceiver comprising one or more appropriatelyconfigured processing circuits, which may in some embodiments beembodied in one or more application-specific integrated circuits(ASICs). In some embodiments, these processing circuits may comprise oneor more microprocessors, microcontrollers, and/or digital signalprocessors programmed with appropriate software and/or firmware to carryout one or more of the operations described above, or variants thereof.In some embodiments, these processing circuits may comprise customizedhardware to carry out one or more of the functions described above. Thepresent embodiments are, therefore, to be considered in all respects asillustrative and not restrictive.

Although multiple embodiments of the present disclosure have beenillustrated in the accompanying Drawings and described in the foregoingDetailed Description, it should be understood that the invention is notlimited to the disclosed embodiments, but instead is also capable ofnumerous rearrangements, modifications and substitutions withoutdeparting from the present disclosure that as has been set forth anddefined within the following claims.

1. A core network (CN) node configured to interact with a plurality ofradio access network (RAN) nodes to time coordinate a plurality of cellsand maintain a reliability of paging a wireless device, the CN nodecomprising: a processor; and, a memory that stores processor-executableinstructions, wherein the processor interfaces with the memory toexecute the processor-executable instructions, whereby the CN node isoperable to: obtain, from one of the RAN nodes, information indicating atime remaining until a next paging opportunity for the wireless devicewithin the cells comprising a paging area of the wireless device.
 2. TheCN node of claim 1, wherein the CN node is further operable to performthe obtain operation by: transmitting a paging request to the one RANnode, wherein the paging request includes information associated withthe wireless device; and, receiving a paging response from the one RANnode, wherein the paging response includes the time remaining until anext paging opportunity for the wireless device.
 3. The CN node of claim2, wherein the information comprises the following: an InternationalMobile Subscriber Identity (IMSI) of the wireless device; an extendedDiscontinuous Receive (eDRX) cycle length of the wireless device; and acoverage class of the wireless device.
 4. The CN node of claim 2,wherein: the paging request is a dummy paging request; and, the pagingresponse is a dummy paging response, wherein the dummy paging request isdefined to trigger the one RAN node to calculate the time remaininguntil the next paging opportunity for the wireless device and thentransmit the dummy paging request which includes the time remaininguntil the next paging opportunity for the wireless device without theone RAN node transmitting a paging message over a radio interface to thewireless device.
 5. The CN node of claim 1, wherein the CN node isfurther operable to: maintain an extended Discontinuous Receive (eDRX)cycle timer associated with the wireless device by using the obtainedtime remaining until the next paging opportunity for the wireless deviceand an eDRX cycle length associated with the wireless device.
 6. The CNnode of claim 5, wherein the CN node is further operable to perform themaintain operation as follows: obtaining updated information indicatingthe time remaining until the next paging opportunity for the wirelessdevice; and modifying the eDRX cycle timer based on the obtained updatedinformation indicating the time remaining until the next pagingopportunity for the wireless device.
 7. The CN node of claim 5, whereinthe CN node is further operable to: set the eDRX cycle timer to expire apredetermined time before the next paging opportunity for the wirelessdevice; upon the expiration of the eDRX cycle timer and based on therebeing a buffered paging message for the wireless device, transmit one ormore paging requests to the one or more RAN nodes managing the cellscomprising the paging area of the wireless device and restart the eDRXcycle timer; and, upon the expiration of the eDRX cycle timer and basedon there being no buffered paging message for the wireless device,restart the eDRX cycle timer.
 8. A method in a core network (CN) nodeconfigured to interact with a plurality of radio access network (RAN)nodes for time coordinating a plurality of cells and maintaining areliability of paging a wireless device, the method comprising:obtaining, from one of the RAN nodes, information indicating a timeremaining until a next paging opportunity for the wireless device withinthe cells comprising a paging area of the wireless device.
 9. The methodof claim 8, wherein the obtaining step further comprises: transmitting apaging request to the one RAN node, wherein the paging request includesinformation associated with the wireless device; and, receiving a pagingresponse from the one RAN node, wherein the paging response includes thetime remaining until a next paging opportunity for the wireless device.10. The method of claim 9, wherein the information comprises thefollowing: an International Mobile Subscriber Identity (IMSI) of thewireless device; an extended Discontinuous Receive (eDRX) cycle lengthof the wireless device; and a coverage class of the wireless device. 11.The method of claim 9, wherein: the paging request is a dummy pagingrequest; and, the paging response is a dummy paging response, whereinthe dummy paging request is defined to trigger the one RAN node tocalculate the time remaining until the next paging opportunity for thewireless device and then transmit the dummy paging request whichincludes the time remaining until the next paging opportunity for thewireless device without the one RAN node transmitting a paging messageover a radio interface to the wireless device.
 12. The method of claim8, further comprising: maintaining an extended Discontinuous Receive(eDRX) cycle timer associated with the wireless device by using theobtained time remaining until the next paging opportunity for thewireless device and an eDRX cycle length associated with the wirelessdevice.
 13. The method of claim 12, wherein the maintaining step furthercomprises: obtaining updated information indicating the time remaininguntil the next paging opportunity for the wireless device; and modifyingthe eDRX cycle timer based on the obtained updated informationindicating the time remaining until the next paging opportunity for thewireless device.
 14. The method of claim 12, further comprising: settingthe eDRX cycle timer to expire a predetermined time before the nextpaging opportunity for the wireless device; upon the expiration of theeDRX cycle timer and based on there being a buffered paging message forthe wireless device, transmitting one or more paging requests to the oneor more RAN nodes managing the cells comprising the paging area of thewireless device and restarting the eDRX cycle timer; and, upon theexpiration of the eDRX cycle timer and based on there being no bufferedpaging message for the wireless device, restarting the eDRX cycle timer.15. A core network (CN) node, comprising: a processor; and, a memorythat stores processor-executable instructions, wherein the processorinterfaces with the memory to execute the processor-executableinstructions, whereby the CN node is operable to: send, to a radioaccess network (RAN) node, a dummy paging request associated with awireless device; and, receive, from the RAN node, a dummy pagingresponse which includes a time remaining until a next paging opportunityfor the wireless device.
 16. The CN node of claim 15, wherein the CNnode is further operable to send the dummy paging request as frequentlyor infrequently as desired to determine the time remaining until thenext paging opportunity for the wireless device.
 17. The CN node ofclaim 15, wherein: the CN node is a Serving General Packet Radio Service(GPRS) Support Node (SGSN); and, the RAN node is a Base StationSubsystem (BSS).
 18. A method in a core network (CN) node for timecoordinating a plurality of cells and maintaining a reliability ofpaging a wireless device, the method comprising: sending, to a radioaccess network (RAN) node, a dummy paging request associated with thewireless device; and, receiving, from the RAN node, a dummy pagingresponse which includes a time remaining until a next paging opportunityfor the wireless device.
 19. The method of claim 18, further comprisingsending the dummy paging request as frequently or infrequently asdesired to determine the time remaining until the next pagingopportunity for the wireless device.
 20. The method of claim 18,wherein: the CN node is a Serving General Packet Radio Service (GPRS)Support Node (SGSN); and, the RAN node is a Base Station Subsystem(BSS).